. >> is defined what a network is an describe it to us. >> sure. that is the holy grail of understanding what the internet is in physical terms. i network on the internet is known as an autonomous system. it operates autonomously. it might be of any scale. it could be a huge network like verizon or telecom. it might be the network of a long-term that spans from new york to los angeles. but is striking and what is necessary to understand is the way it manifests itself physically that networks carried networks. you might have a level 3 that owns the strands of glass and on the conduits that perhaps spread like railroad tracks across the country. there are midsize network companies that might shall illuminate those glass. they might own the light. there is another company, maybe a goldman sachs or a large law firm, that advises on that glass. ee often talk about the interi information superhighway. i like to think of it more that a network is a car that is tugging along the highway side- by-side with other networks. there is definitely a layering goin